Join Date: Feb 2004
Thanked 0 Times in 0 Posts
Rep Power: 13
Hi. I am a professional metal worker (Qualified as a blacksmith, worked as a boilermaker and eventually did a secondary degree in fine art metal (gold and silver smithing). I have also worked in casting metals and in destruct testing and failure analysis.)
I have absolutely no dog in this fight, in fact, I am in another country.
Now havign said all that...the stuff that was being said regarding jet fuel not being able to melt steel, and steel melting is what caused the towers to fall is utter tripe.
Firstly, it is not about jet fuel burning hot enough to melt steel. It does not need to happen. What you have are two huge chimneys that draw amazing amounts of air at huge volocities once there is a fire that causes airflow to begin drawing. In this case the central elevator shafts acted as a nearly perfect flue. Like using bellows on charcoal in order to jump from 300degrees C to 1200 degrees C...the key is airflow. And the thing is that at that point, it was not the jet fuel that was burning, that was just an initial source of ignition, on its own, it would not deliver a long lasting thermal source. My guess is that it was all burnt away within 5 minutes at the outside...but by then it had coated just about everything and caused a huge area of carpets, furnishings, noise insulation and everything else including plaster wall panels to ignite and commence releasing their thermal potential. You were no longer burning jet fuel, that was just your lighter fluid, now the real barbeque grill could do its work...and it had 1100 feet of draw.
That will melt steel handily.
I have built 8th century bloomeries that smelt iron using homemade charcoal and some twigs...it is all about the airflow.
Now lets talk about the other really important misunderstanding displayed in your post. The steel that actually brought about the collapse did not need to come anywhere near to melting tempreture. The steel used to hold the floors in that building was tempered trusses. This means a fairly lightweight structure that delivers its strenght by means of its shape and by the fact that all individual components are heat treated to attain maximum strength (but shy of the point at which they become too brittle). This is a bit of atricky process to get right when dealing with huge trusses. The facilites for making them are pretty impressive.
But here's the downside....All it takes is enough heat to take the temper out of the steel, or enough to just warp the truss so that its shape is no longer aligned to precisely deal with the weight it is supporting...and it begins to fail.
It takes less then 500 degrees C to take the temper off much better steel then was used in the trusses and "normalise" it...except that normalising is what happens if you just let it col normally under no strees....In this case, it had 100's of tons of weight pressing down on it.
Now I want you to try a little experiment. Take a little strip of 18ga mild steel and flex it between your hands a few times. really give it a good fold and then back out. Now touch the fold point...Hot isn't it?
Now imagine steel that has been de-tempered and weakened by heat, under many hundreds of tons of load, in an oven environment (unable to shed heat)...going taffy and drawing out as it gives. Basically, the steel failing is what contributed the last bit of heat needed to generate the melted look of many peices.
So your conspiracy theories may be valid or about as much use as a hat made of blue cheese...You are welcome to them regardless...but the beliefs you espoused about steel were just plain silly.
You claim that you enjoy doing intensive research, so I do not feel too bad about providing the 2am ssuper basic version of what I was saying.I hope it inspores you to do some research further afield then you seem to have looked to date.